Intro to Coding

Rules to follow when writing code:

1. Use principles as guide in unknown territory
2. Simple classes
   • Should
     • be immutable
     • ideally : private final Type field; . If really needed public final Type field;
     • initialized once at construction time
   • Should Not
     • have getters/setters
3. The absolute needed libraries are:
   • junit - testing api
   • slf4j - logging api - Intro to Logging
   • logback - simple logging implementation
   • guava - google utilities
4. Careful on exception idioms
   • Never swallow an exception. If in doubt rethrow it.
   • principle~Fail Fast
   • A logged exception at info level is always a bug.
   • The exception should give enough details to be able to investigate the problem without debugging. If the investigation lasts more than 30s you have a bug on investigation of the exception.
   • see Checked Exceptions vs Unchecked Exceptions
5. Do not use
   • static fields
   • null (use java.util.Optional) - Null Object
     • Do not have references to null objects.
     • If you could return null better to return Optional.empty()
6. Try to use
   • final fields
7. Beans, Getters and Setters are overhyped

• Immutable classes (do not confuse with final fields)